ATP, Water and Inorganic Ions

Question 1

Why is ATP useful?

Answer 1

• Release energy in small amounts.
• Broken down in single reaction (releases energy rapidly).
• Add phosphate to other molecules (makes them more reactive).
• Easily resynthesised.

Question 2

What does ATP stand for?

Answer 2

Adenosine Triphosphate.

Question 3

What doe ADP stand for?

Answer 3

Adenosine Diphosphate.

Question 4

What does ATP synthase do?

Answer 4

Form ATP from ADP + Pi.

Question 5

What does ATP hydrolase do?

Answer 5

Breaks down ATP into ADP + Pi.

Question 6

What is ATP made up of?

Answer 6

• Ribose.
• Adenine.
• Three phosphate groups.

Question 7

Why is hydrolysis of ATP useful?

Answer 7

can be coupled with energy requiring reactions within cells.

Question 8

What is released in the hydrolysis of ATP and how it is used?

Answer 8

Inorganic phosphate is released which can be used to phosphorylate other compounds, making them more reactive.

Question 9

What is the structure of water?

Answer 9

Its a polar molecule made up of two hydrogen atoms (slightly positive) and one oxygen atom (slightly negative). These atoms are held together by covalent bonds.

Question 10

How do water molecules bond to each other?

Answer 10

The polarity of water allows weak attractions called hydrogen bonds to form between water molecules; the negative oxygen atom of one water molecule attracts the positive hydrogen atom of another water molecule.

Question 11

What is a solvent?

Answer 11

A liquid that other substances can dissolve in.

Question 12

Why is water know as the universal solvent?

Answer 12

Due to its polarity, with many chemical reactions taking place in aqueous solutions. Charged or polar molecules readily dissolve in water while uncharged molecules do not.

Question 13

How does sodium chloride dissolve in water?

Answer 13

Sodium chloride (NaCl) produces positive sodium ions and negative chlorine ions when it is dissolved in water. The positive oxygen molecule in water attracts the negative chlorine ions, while the negative hydrogen molecules in water attract the positive sodium ions.

Question 14

Why is water known as a metabolite?

Answer 14

Water is important in many reactions (e.g. condensation & hydrolysis).

Question 15

What is cohesion?

Answer 15

Water molecules stick to each other because of their hydrogen bonds.

Question 16

Why is cohesion an important characteristic of water?

Answer 16

• Makes it possible to pull water uphill (e.g. xylem)

- Responsible for surface tension when water meets air (pond skaters).

Question 17

What is meant by water having a high latent heat of vaporisation?

Answer 17

It takes a lot of energy to break the hydrogen bonds between the molecules. This means evaporation is an effective form of cooling.

Question 18

What is meant by water having a high specific heat capacity?

Answer 18

It takes a lot of energy to heat up or cool down water because of the hydrogen bonds between its molecules. This means that aquatic environments remain a relatively stable temperature.

Question 19

What characteristic of water allows our internal body temperatures to change slowly?

Answer 19

High specific heat capacity.

Question 20

What is an ion?

Answer 20

An atom that has left or gained electrons.

Question 21

What is meant by the term inorganic?

Answer 21

A compound that doesn’t contain carbon.

Question 22

Where do inorganic ions occur?

Answer 22

In the cytoplasm and body fluids.

Question 23

What is pH a measure of?

Answer 23

H+ ions in a solution.

Question 24

Why are sodium ions important?

Answer 24

They help to move other molecules across membranes (Co-transport).

Question 25

Why are iron ions important?

Answer 25

Important in haemoglobin as they carry oxygen.

Question 26

Where are phosphate ions important?

Answer 26

In ATP and in RNA/DNA (condensation reactions between phosphate groups to form polynucleotides).